"Everyone is getting married on that day,” Ivy Ha — an Oakland, California wedding planner — told the Mercury News. Her business is involved in 10 weddings on Aug. 18, which is more than double the number she does on a typical summer Sunday.

There's a number of possible reasons for the popularity of the date:

Easy to remember

8 1 8 1 8: It reads the same backwards and forwards.

“A lot of couples picked it for the significance of the date, it’s a palindrome month,” Ivy Jacobson, an editor at the Knot, told Forbes.

In Houston, a married couple who owns a bakery can understand the popularity of Aug. 18 — they also got married on a memorable date: 9-7-97.

Bobby and Janice Jucker, owners of Three Brothers Bakery, said they were busy in the lead up to Aug. 18. So busy, they didn't even realize the significance of the date.

The owners of China Village Seafood Restaurant in Belmont, California, were also busy — their restaurant had been booked for over a year and they've had to turn away over a dozen couples, according to KGO-TV.

It's lucky

Ha told the Mercury News that “Eighteen is a lucky number, especially with Chinese people.”

When spoken in Mandarin, the number sounds like a phrase that means “certain prosperity," she told the publication.

In Jewish culture, 18 is connected with the concept of "Chai" — which translates to "Life," according to the International Fellowship of Christians and Jews.

The two letters that make up "Chai" in Hebrew each have a number value; together, they add to equal 18, the organization says.

It's symbolic

The number 8 also looks like the infinity sign — which can be symbolic of love.

“The eight is like an infinity symbol. Three eights is super lucky": That's how one couple described their reason for picking the date according to Bart Willner, owner of a tuxedo store in San Jose, California, according to the Mercury News.